Add support for new scroll valuators coming from CMT

ui/aura/root_window.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_AURA_ROOT_WINDOW_H_
 #define UI_AURA_ROOT_WINDOW_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
@@ skipping 20 matching lines @@
 }
 
 namespace aura {
 
 class RootWindowHost;
 class RootWindowObserver;
 class KeyEvent;
 class MouseEvent;
 class ScreenAura;
 class StackingClient;
+class ScrollEvent;
 class TouchEvent;
 
 // RootWindow is responsible for hosting a set of windows.
 class AURA_EXPORT RootWindow : public ui::CompositorDelegate,
                                public Window,
                                public internal::FocusManager,
                                public ui::LayerAnimationObserver {
  public:
   static RootWindow* GetInstance();
   static void DeleteInstance();
@@ skipping 27 matching lines @@
 
   // Draws the necessary set of windows.
   void Draw();
 
   // Handles a mouse event. Returns true if handled.
   bool DispatchMouseEvent(MouseEvent* event);
 
   // Handles a key event. Returns true if handled.
   bool DispatchKeyEvent(KeyEvent* event);
 
+  // Handles a scroll event. Returns true if handled.
+  bool DispatchScrollEvent(ScrollEvent* event);
+
   // Handles a touch event. Returns true if handled.
   bool DispatchTouchEvent(TouchEvent* event);
 
   // Called when the host changes size.
   void OnHostResized(const gfx::Size& size);
 
   // Called when the native screen's resolution changes.
   void OnNativeScreenResized(const gfx::Size& size);
 
   // Invoked when |window| is initialized.
@@ skipping 116 matching lines @@
   Window* mouse_moved_handler_;
   Window* focused_window_;
   Window* touch_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindow);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_H_